package org.example;

import java.util.ArrayList;
import java.util.Collections;

public class Function_Demo1 {
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        Collections.addAll(list,"1","2","3","4","5","6","7","8","9");
        list.stream().map(Integer::parseInt).forEach(System.out::print);
        System.out.println();
        //方法已经存在
        //方法形参和返回值需要跟抽象方法的参数和返回值类型一致
    }
}
